MgAl-LDH/graphene protective film: Insight into LDH-graphene interaction

MgAl-layered double hydroxides (LDHs) thin films, exhibiting two distinct surface morphologies (Platelet and Cauliflower-like), were synthesized directly on the aluminum substrate. The as-prepared films were further modified with graphene due to the chemical inertness of graphene and its capability to act as a possible physical barrier against ionic media. The morphology and structure of MgAl-LDH/graphene composite films are fully characterized. The corrosion resistance properties were analyzed through Electrochemical impedance spectroscopy and the results were further fitted using ZSimpWin software to evaluate coating behavior. The graphene was found to interact with the LDH structure and provide another pathway for the corrosion reactions and results in improve LDHs corrosion resistance properties. The sealing effect of graphene resists the aggressive media penetration and caused an increase of one order magnitude in impedance modulus of MgAl-LDHs. The enhancement in corrosion resistance properties is attributed to the graphene impermeable behavior against corrosive species confirmed by physical and electrochemical characterizations.